package com.mmall.seckill.util;

import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.StringUtils;
import org.codehaus.jackson.map.DeserializationConfig;
import org.codehaus.jackson.map.ObjectMapper;
import org.codehaus.jackson.map.SerializationConfig;
import org.codehaus.jackson.map.annotate.JsonSerialize.Inclusion;
import org.codehaus.jackson.type.JavaType;
import org.codehaus.jackson.type.TypeReference;

import java.text.SimpleDateFormat;

/**
 * json序列化和反序列化工具类
 * Created by megan on 2017/12/23.
 */
@Slf4j
public class JsonUtil {

    private static ObjectMapper objectMapper = new ObjectMapper();

    private static final String STANDARD_FORMAT = "yyyy-MM-dd HH:mm:ss";

    static{
        //对象德尔所有字段全部列入
        objectMapper.setSerializationInclusion(Inclusion.ALWAYS);

        //取消默认装换timestamps形式
        objectMapper.configure(SerializationConfig.Feature.WRITE_DATE_KEYS_AS_TIMESTAMPS,false);

        //忽略空bean转接送的错误
        objectMapper.configure(SerializationConfig.Feature.FAIL_ON_EMPTY_BEANS,false);

        //所有的容器格式都统一为以下的格式,即yyyy-MM-dd HH:mm:ss
        objectMapper.setDateFormat(new SimpleDateFormat(STANDARD_FORMAT));

        //忽略在json字符串中存在,但是在Java对象不存在的对应属性的情况。防止错误
        objectMapper.configure(DeserializationConfig.Feature.FAIL_ON_NULL_FOR_PRIMITIVES,false);

    }

    /**
     * Object --->> Str
     * @param obj
     * @param <T>
     * @return
     */
    public static <T>String obj2String(T obj){
        if(obj == null){
            return null;
        }
        try {
            return obj instanceof  String ? (String)obj : objectMapper.writeValueAsString(obj);
        } catch (Exception e) {
            log.warn("Parse Object to String error",e);
            return null;
        }
    }

    /**
     * Object --->> Str
     * @param obj
     * @param <T>
     * @return 格式化化好的str
     */
    public static <T>String obj2StringPretty(T obj){
        if(obj == null){
            return null;
        }
        try {
            return obj instanceof  String ? (String)obj : objectMapper.writerWithDefaultPrettyPrinter().writeValueAsString(obj);
        } catch (Exception e) {
            log.warn("Parse Object to String error",e);
            return null;
        }
    }

    /**
     * Str -->> Obj
     * @param str
     * @param clazz
     * @param <T>
     * @return
     */
    public static  <T> T string2Obj(String str, Class<T> clazz){
        if(StringUtils.isEmpty(str) || clazz == null){
            return null;
        }
        try {
            return clazz.equals(String.class) ? (T) str : objectMapper.readValue(str,clazz);
        } catch (Exception e) {
            log.warn("Parse String to Object error",e);
            return null;
        }
    }

    /**
     * obj--->obj
     * @param str
     * @param typeReference
     * @param <T>
     * @return
     */
    public static <T> T string2obj(String str,TypeReference<T> typeReference){
        if(StringUtils.isEmpty(str) || typeReference == null){
            return null;
        }
        try {
            return (T) (typeReference.getType().equals(String.class) ?  str : objectMapper.readValue(str,typeReference));
        } catch (Exception e) {
            log.warn("Parse String to Object error",e);
            return null;
        }
    }

    public static <T> T string2obj(String str,Class<?> collectionClass,Class<?>... elementClasses){
        JavaType javaType = objectMapper.getTypeFactory().constructParametricType(collectionClass,elementClasses);
        try {
            return objectMapper.readValue(str,javaType);
        } catch (Exception e) {
            log.warn("Parse String to Object error",e);
            return null;
        }
    }
}
